1. Technical Field
The invention relates to the processing of digitized images. More particularly, the invention relates to an image reconstruction architecture in which digitized images that are obtained from an image source, such as a scanner, are processed for output to an output device, such as a printer.
2. Description of the Prior Art
In image processing, image signals typically undergo various adjustments or corrections. For example, when printing a digitized image these adjustments and corrections can include:
Color adjustment;
Deskewing;
Background and dust removal;
Descreening;
Text detection;
Text Enhancement;
Color conversion;
Scaling; and
Color manipulation.
In most image processing systems, digitized image signal correctors perform the adjustments or corrections based on the processing parameters provided by the operators. The task of selecting the appropriate processing parameters for these digitized image signal correctors to achieve certain desired output results is normally left to the operator and is one of the more difficult tasks in image processing. As the complexity of the image processing model grows with advances in image processing technology, this task has become even more difficult.
In most if not all adjustments or corrections, the operator typically does not want to know about the particular processing parameters being used, he simply wants to achieve the desired output results. Thus, it is desirable to be able to determine the optimal processing parameters for digitized image signal correctors automatically on an image processing system to correct digitized signals to achieve specified output results for an image.
Examples of automatic or semi-automatic image processing systems include E. Spiegel, M. Broudo, R. Lavie, Y. Bresler, Y. Pluda, E. Baron, Apparatus and Techniques For Processing of Data Such As Color Images, U.S. Pat. No. 5,615,282 (Mar. 25, 1997) and P. Capitant, D. Collier, Correcting Digitized Signals To Achieve Specified Output Results For An Image, U.S. Pat. No. 5,467,412 (Nov. 14, 1995).
However, such systems provide only limited image reconstruction capability. For example, such systems do not incorporate descreening or text detection facilities, such that an image reconstruction subsystem must be appended thereto. Further, such systems do not provide multiple data paths, e.g. for single and multiple scans, nor do such systems support both contone and 1-bit printing.
It would be advantageous to provide an improved method and apparatus for reconstructing digitized images.
The invention provides an improved method and apparatus for reconstructing digitized images. The invention processes one or more color formats, e.g. contone or 1-bit, and readily operates with image sources that can include both single and multiple scan systems. For purpose of the discussion herein, multiple scan refers to systems that scan an image once per print separation, i.e. for a CMYK printing system the image is scanned four times, and printing separations for C, M, Y, and K are generated one by one; and single scan refers to copy systems that scan an image once for all print separations, e.g. for a CYMK printing system the image is scanned once.
The preferred embodiment of the invention provides an image reconstruction path that receives a digitized image, e.g. from a scanner or from memory. The output of the image reconstruction path is a processed RGB or CMYK image that may be printed or stored in memory. The image reconstruction path itself is configured to operate in either of a multiple scan or single scan environment when the source of the digitized image is a scanner. Within the image reconstruction path there are a plurality of functional units that can be controlled by user or internal controls, or that can be optionally bypassed. These functional units can include any of a preliminary color adjustment function, an automatic deskew function, a background and dust removal function, a descreen function, a text detection and enhancement function, a color conversion function, a scaling function, and a color manipulation function. It will be appreciated by those skilled in the art that other functions may be provided.
An important feature of this architecture is that it is open-ended on both the input and output ends. This means that with the appropriate customization it is ready to accommodate different scanners at the input source and different printers at the output target.